Control system



Sept. 23, 1941. M. J. JOHNSON CONTROL SYSTEM Filed Feb. 1, 1958 2 Sheets-Sheet l D In O I O I I I Q LO Job 6071,

INVENTOR Manfredi Sept. 23, 1941-.

JOHN SON CONTROL SYSTEM Filed Feb. 1, 1938 2 Sheets-Sheet 2 Olll'll INVENTOR Man/red J. J0Z771s077 ATTORNE Patented Sept. 23, 1941 CONTROL SYSTEM Manfred J. J ohnson, Naugatuck, (am, assignor of one-half to The Lewis Engineering Company,

Naugatuck, Conn.

Application February 1, 1938, Serial No. 188,942

Claims. (El. TWP-278) The present invention relates to control and/or indicating systems, and more particularly to control and/or indicating systems for compeneating for and/or indicating changes in a condition.

In many devices, it is desired, during normal operation, to maintain a desired condition. In order to do this, it is necessary to have a control and/or indicating system which, when actuated, will compensate for and/or indicate variations from the normal condition. To be suecessful, such systems must be flexible, efficient and quick acting so as to be sensitive to, the variety of changes in condition which are olesired to be corrected and/or indicated.

Another requirement is that the control system must be accurate inlts operation so that in correcting for the change in condition it will not overrun or move past the corrected position and thus set up a period oi hunting during which the device will operate first to one side and thento the other side of the normal condition until the normal condition is gradually reached.

ance with the direction and magnitude. of the changed condition.

In one form of the invention, a pair of electron tubes are connected, one to each shading coil, so as to have their plates energized therefrom and the control for the flow of electrons is actuated by the actuator tor the controlling device. When a change in conuitlouoccurs in the device to be controlled, the actuator will move and through connected circuits control the flow of electrons in one or the other of the electron tubes in accordance with the direction and magnitude of the changed condition so that the associated shading coil becomes loaded and causes the controlling motor to operate in the desired direction to thereby actuate the controlling mechanism of the device to be controlled to correct and/or indicate the changed condition, When the condition is corrected, the leasing will he removed from the shading coils and the motor will again become balanced and immediately operate to brake any further movement of the The present invention relates broadly to a control and/or indicating system and is a continuation in part of my concluding applications, Serial No. 35,151, filed August '4', 1935, now Patent No. 2,109,776, issued March 31, H38, and Serial No. 1%;085, filed Got. 1%, W36, having a reversible motor provided with inherent braking means and having its rotation controlled by means oi an actuator through the medium of electron tubes. This system of control uses small ill currents, prevents sparking and is quickly responsive to changes. The controller can be manually actuated but preferably is connected to a means adapted to be operated in response to a change in condition to be corrected and/or indicated. When connected to the device to be controlled, the system will accurately compensate for and/or indicate changes from the nor mal condition and will quickly regulate the device in accordance with the directionanrl magnitude of the variation from the normal condi tion without overrunning or hunting so that the highest degree of accuracy is obtained.

. According to the present invention, a reversible A. C. motor having opposed wire-wound shading coils is used to actuate the controller mechanism for the device to be controlled. Themotor has a pair of wire-wound shading coils normally balanced so that it is in effect braked against rotatiom The shading coils are connected to be controlled by electron tube means in accordcontroller.

in another form of the invention, the re versihle motor has the shading coils normally balanced and a switching means is provided for alternately coupling one or the other or? the shading coils to a single electron tube. e is connected to a pair of spaced contacts and its operation is controlled by an actuator which moves in response to a change of condition in the machine to be controlled. The spaced con= tacts and switching means operate in timed relation so that changes in direction and magni= tude of the condition will cause the actuator to close a circuit through the contact and u nchronously therewith the switching means will couple the shading coil corresponding to such contact with the electron tube and time lead the corresponding shading coil to cause the control ling motor to operate in predetermined direction to correct for the changed condition.

The control and/or indicating system of the present invention obviously can he used in such a manner that it will control a device so as to compensate for changes in condition and can, at the same time, indicate the extent or such change or it can be operated to indicate the chan'gein condition whereby it can be otherwise corrected as desired.

Other features and advantages of the inven tion will be apparent from the specification and claims when taken in connection with the drawings, in which: t

Figure l is a diagrammatic view showing the tube - lustments of vontion and the apparatus emther form of system of this atus embodied therein. resent invention, :2. reversible ed for operating the control or mechanism. This motor can so which can be accurately direction operation.

end/or indies he any tie. I rolled in sod form of the invention, alt current motor escalated v11 1 u 1: of iiclcl constenbl oils and the two coils EC It will be understood ngs of the shading coils i9 are e" oru 1r 5., the rotor will turn in one direc flue windings of the shading oils .ortcircuited, the rotor will one pair of ShCl'lrrotor will he brou opposition of the s c ecteristics o vsntogeous to or circuited shading coils, the it to an abrupt stop, due to "cling coils is and These type of motor ere adtrollers. It is found that, by having t.e f eld pieces of the motor constsntly energized, response of the'motor is almost n'stsntsneous, and it quickly accelerates and yet stops quickly and suddenly upon the opening of the short-circuited shading coils due the mutual opposition of the shading coils l9 and is this type of control, I am able to bring controller to the desired position without o danger or overthrow which would result in iting, and thus reduces substantially the time necessary for one-sting a desired control.

The motor can be connected to a controller 9' /or indicator as by a control shaft 23, in any ed manner. In order to obtain a desired operating speed for the shaft 23, a gear 24 is mounted on the motor shaft in mesh with a gear 25 on the control shaft so that rotation in either direction of the motor will operate the control shaft 23 in either direction, which will in turn operate the mechanism to control the device as desired. The shaft 23 can carry an indicating pointer 26.

The means for controlling the motor as desired, comprises an actuator 21 which is movably mounted and has its contacting end of conducting material. This actuator can be either pivotally mounted or otherwise movably mounted in such a manner as to have a normal zero or open-circuit position from which it can be moved to control the motor as will be explained. In the preferred form of the invention, the actuator is adapted to begconnected to a means on the device to be controlled which will move the actuator in either direction from a normal or zero erconnected for simultaneo-- position. A pair of contacts 28 and 29 are positioned to be contacted by the actuator when it is moved in cit-her direction from the ofl-zero posltion.

Off-zero movements of the actuator are transmitted to the controlling motor by means 0! devices which are adapted. to load the opposed pairs of shading coils in accordance with the closing of the circuit through either of the contacts 28 or 29 by the actuator 21. In the herein pre 'ferred ion": of the invention, these circuits include elect l tubes. electron tubes is meant t! connected resrwctivcly by w r to the directional contacts and '25, the wires Lu being connected by high resistances 38 and 53a, between which there is a lead 39. The filaments of the two tubes are connected in par-- allel and to wires 40 leading to the winding M of s. transformer 42, the primary 43 of which is connected the supply wires l5 and H5. The transformer 32 has two other secondary windings H and 45 similar to other and having a com 1011 terminal effecting e series plus to minus connection and connecting to the center top of the filament winding 4i and through wire 48 to an intermediate point 41 of a coupling transformer 8 winch couples the shading coils to the thermlon'lc devices. The remaining end of the secondary coll H is connected to a resistor 49 which is connected to the actuator 27. The transformer 8 couples the shading coils to the thermionic devices for energizutldn therefrom. The transformer has primary windings 52 and 53 connected respectively to the shading coils l9 and 20. The shading coils have a common return wire I! leading to the common terminal 55 of the primary windings of the transformer 48. The secondaries 66 of the transformer have a. common connection at 41 such that the two remaining ends are either positive, zero or negative polarity at any instant, and these remaining ends are connected individually and respectively to the plates I4 01 the thermionic devices 30 and 3|.

Voltage is induced in the shading coils I! and N, due to the A. C. energlzatlon of the field coll N. This voltage energizes the transformer 48 and induces in the secondaries relatively high A. C. voltages to be impressed on the plates of the thermionic devices 30 and 3!. Thus, each plate is alternately positive and negative, and the connections of the secondary coil make the ends of the secondaries 56 of the same polarity and insure that both plates will be positive, zero or negative in polarity at the some time.

As iswell known, in thermlonic'tubes a plate current will-w only when a suflicient positive.

charge is impressed on the plate. The energlzatlon of the two transformers l2 and 48, irom the same sixty-cycle supply line and the shading coils, will respectively always have a. constant phase relationship, due to the one ultimate source of supply, namely, wires l5 and I6. This relationship is such that when the plates of the devices 30 and 3! are both positively energized, the grids of these devices are negative due to their connection to wire 39 and the negative side of the secondary coil 48 of the transformer 42, all provldlng no contact is made through the actuator tube is used to load either pair of shading coils so that the motor will be rotated in the desired direction. As in the other form of the invention, any type of tube, in which electron flow can be controlled, may be used. In the herein disclosed form of the invention, a three-element thermionic device is used, the device havin a grid 85, filament and plate 8?.

The directional contacts $5 and 68 are connected to end plates 89 and 89 on the drum, and pair of brushes El and 92 are positioned to engage the contacts during rotation of the drum. These brushes are connected by a common wire to the grid &5. The filament 86 oi the thermionic device 84 is connected by wlres tell to the filament coil 3&2 or a transformer 3?.

The actuator is connected by a wire 94 through a grid resistor to e, secondary or grid cold 96 of the transformer ill, the primary winding S8 of the transiormer being disposed across the lines it": and 66. The coil 55 has a center tap connected by 2. wire QM with the center tap of the filament coil ill? and the remaining end of the coil 56 is connected by e. wire 99 through a grid resistor too to the wire 93 leading to the grid of the thermionic tube. A wire MM is connected to one end of the secondary I05 of the transformer 75. The other end of the secondary is connected by a wire ME to the plate 81 of the tube at.

It will be seen that when the actuator is not engaging either contact of the drum, the grid of the tube 84 will have impressed on it an alternating voltage from the coil 86 through the resistor loll.

According to this i'orm of the invention, this voltage is synchronized with an alternating voltage applied to the plate but is in phase opposition to said voltage. This is accomplished by having the field coil H of the motor connected to the supply wires l5, it in such a manner that the induced voltages of either set of shading coils of the motor will, when the single-pole double-throw switch is in closed position, energize the transformer 75 so that the secondary coil lilS thereof impre s the desired voltage of opposite polarity to that of the grid on a plate 3? of the tube S.

When the controller is in a zero position, no current will flow in the plate circuit or the thermionic device 3%, since, during intervals that the plate of said device is positive, the negative bias on the grid is sumcient keep the plate periodically by the ball 10, connect one or the other of the contacts 5 or I! through the resistor 95. The resistor 85 is preferably of equal value to that of resistor Ill so that, as a consequence or the contact caused by the actuator, the voltage on the grid of the tube 84 will be reduced to substantially zero and during intervals of positive polarity of the plate,- a. current will flow in the plate circuit and load, as determined by the position of the single-pole double-throw switch, a set of shading coils so as to cause the motor to rotate in the desired ascaveo direction. Thus, movement of the actuator can, depending on the position of the switch, load either set or shading coils to cause rotation of the motor in either direction.

As shown in Fig. 2, the single-pole doublethrow switch is actuated automatically with the rotation ol. the drum 6! so as to associate with the theremionic device the proper set of shading coils when the directional contact for rotating the control motor in the desired direction is in a position to be engaged by the actuator should it be deflected in that direction from zero position.

Preferably, the cam 82 and switch are so arranged that the latter closes a shading coil circult before contact can be established to either of the contacts 65 or 66 and opens the shading coll circuit after this engagement with either 0! the drum contacts is broken. Thus, there will be positively no arcing at the contacts of this switch since contact is made and broken during the periods when current of the shading coils is extremely low, as no plate current can flow unless either of the drum contacts is engaged by the actuator.

The motor 68, which is connected across the supply lines i5 and I6, is preferably of s type having a speed such that it will turn suiliciently slowly relative to the frequency 01' the A. C. energization of the system that several alternations of current will take place during a period 01 contact between the actuator 84 on either of the contacts 55 or 66 when the actuator is out 0! zero position.

With this construction, it will be seen that one of the electron tubes can be dispensed with and the single remaining tube can be coupled to the shading coils of the motor selectively and in definite timed relation with the presentation of the contacts for cooperation with the actuator when the latter deflects in either direction in order to produce the desired rotation of the motor. As soon as the condition to be corrected returns to normal and the actuator returns to zero position, the bias on the grid becomes negative again and the plate current stops so that the shading coils are no longer loaded. The balanced fields will immediately stop rotation of the rotor and prevent the mechanism being controlled from overrunning and hunting.

From the foregoing, it will be seen that I have produced a controlling mechanism which is accurate and eflicient in operation and which will correct any changes without overrunning or hunting.

Variations and modifications may be made within the scope or this invention and portions of the improvements may be used without others. I claim:

1. In a control apparatus, an alternating current motor operative in reverse directions; control circuits for controlling the direction of operation of said motor; a movable actuator; switch means including contact rendered operable by the actuator and connected in said control circuit for periodically closing and opening a. circult according to a given constant period when said actuator moves in one direction and for periodically closing and opening the circuit according to a similar period when the actuator moves in the other direction, said periods being in constant phase opposition and in predetermined relation with the voltage impressed on said motor; and circuit-control means connected with said switch means and control circuits and aurelation with eluding automatic switch means for alternately connecting each coil; a movable actuator; and

means for causing periodic functioning of the discharge device to periodically drive the motor in response to the movement of the actuator,

' periods'of functioning due to the movement in time of said motor; an electron tube system con rent motor having a continuously energized A, C

field and a pair oi oploositelt disposed wirewound pole shadine coils; a control circuit for controlling the direction of operation of motor; an electron discharge device; means connecting said device with the control circuits for operation of the motor by the device; a movable actuator; means, including contactsfcooperable with the actuator and operable in response to movement oi said actuator controlling the functioning of the electron discharge device; and 'circuit control means connected in said con-=- trol circuit and automatically operative in timed the last-mentioned means for causing the electron discharge device to so alternately connected to one oi the sets oi shading coils to operate the motor in one directionor the other, depending on the direction of movement or the actuator.

Ln a control apparatus, a reversible A. (3. motor having a continuously excited held and oppositely disposed wire=vvound shading coils; an actuating member having a normal zero position and movable to either side oi the zero position in accordance with the magnitude oi a condition; a thermionic device; a circuit con trolled by the off-zero movements oi the actustar and connected with the grid of the ther niionic device, including means for polarizing said grid; means coupling the wire-wound shad the coils oi the motor to the plate of the their mionic device, said means including a trans iormer whereby voltages induced in the shading coils are impressed on said plate; means con-- nected with the shading coils for selectively con meeting the coils to the transformer; means connected to the actuator for causing the grid of the thermionic device to become depolarized to cause current to flow in the plate circuit and. make operative the shading coil energizing said circuit to cause rotation oi the motor; and

means for automatically operating the shading coil connecting means concurrently with the grid-depolarizing means comiected to the movable member.

5. In a control apparatus, a reversible A. C. motor having a continuously excited field and a pair of oppositely disposed wire-wound shading? coils; an electron discharge device i'or operating the motor; means for connecting the shading coils of the motor with the discharge device intiznetl relation with the last tilt one direction corresponding to the periods of connection oi one shading coil and the periods of i'unctioninu due to the movement in another 5 direction corresponding to the periods or council- .tion in theother shading coil. Y

6. In a control system, means to be driven; means connected to said means, including a reversible A. C. motor having a continuously can cited field and oppositely disposed wire-Wound shading coils; an electron discharge device; means for coupling the electron discharge oevice to the shading cone or the motor; automatic switch means in the circuit tor the shading cone for alternately connecting each coil; 12. movaole actuator; and means tor causing periodic iunction of the discharge device ill response to move ment of the actuator, the periods or iunctioning clue to movement in one direction corresponoins to the periods or connection of one shading coil and the periods oi iunctioninsolue to the move ment in the other direction corresponding to the periods of connection of the other shading coil" 7. in a control system, a reversible A. C, motor having" a continuously excited held and a pair oi oppoositely disoosed wire-wound shading an electron discharge device ior operating the motor; means ior coupllm; the shading coils the motor with the discharge device; a movable actuator; means tor causing oeriotlic functioning according to a constant frequency oi the di charge device in response to movement oi the actuator incite direction and for causing lar periodic function oiltlie discharge device response to movement oi the actuator other direction, the periods oi the latter .iunc tioninc being in phase opposition with the mentioned periods; andmeans connected with the shading coils for alternately connecting the coils to said coupling means in step with t periods of functioning oi the discharge device 6. in a control apparatus, an electro respou sive means operative in reverse directions; movable actuating member; an electrical system for operating said responsive means in one direc tion or the other in response to movement oi member-in one direction or the other respectively, said system iiicludii'i g means cogs-gentile by the movable actuating member for causing intermittent operation according to a given con, stant period of electro responsive means upon movement oi the meinloer in one direction and.

tor causing similar intermittent operation oi the electro-resoonsive means upon movement oi member in the other direction, the periods said intermittent operation loeing substantially in phase opposition; continually operative direction-selecting means connected with the electro responsive means for continuously reversing the direction in which the electro-responsive means is operative, said selecting means operating in svnchronism with the periodicity of the iutermittent operations of the electro-responsive means resulting from movement of the actuator in either direction; and circuits for coupiimi said means actuated by the movable member with the selectingmeans.

9. In a control system, a. reversible A. C. motor having a continuously excited field and oppositely disposed wire-wound shading coils; an electron tube device; means for coupling the electron tube device to the shading coils of the motor to be energized therefrom; automatic switch means in the circuit for the shading coils for alternately connecting each coil; a movable actuator; and means for causing periodic functioning of the tube device in response to movement of the actuator, the periods of functioning, due to the movement of the actuator in one direction corresponding to the periods or connection of one shading coil and the periods of functioning due to movement or" the actuator in the other direction corresponding to periods of connection with the other shading coil.

10. in a control apparatus, an electro-responsive means operative in reverse directions; control circuits, for controlling the direction of on eration of said means; a defiectable member; switch means actuated by the defiectable member, and connected in said control circuits, for periodically closing and opening a circuit according to a given constant period when the said member deflects in one direction, and for periodically closing and opening the circuit according to a similar period when the member deflects in the other direction, said periods being in constant phase opposition; and means connected with said switch means and control circuits, and automatically actuated in synchronism with the periods of opening and closing of the switch means,.for causing the electro-responsive means to operate in one direction when the defiectable member deflects in one direction, and for causing the electro-responsive means to operate in the reverse direction when the member deflects in the other direction, in which the switch means includes a contact directionally movable by the deflectable member, a pair of contacts for engagement with the first contact, and means for periodically alternately bringing the contacts of said pair into the field of action of the directionally movable contact.

11. In a control apparatus, an electro-responsive means operative in reverse directions; control circuits, for controlling the direction of operation of said means; a deflectaole member; switch means actuated by the deflectable memher, and connected in said control circuits for periodically closing and opening a circuit according to a given constant period when the said member deflects in one direction, and for periodically closing and opem'ng the circuit according to a similar period when the member deflects in the other direction, said periods being in constant phase opposition; and circuit control means connected with said switch means and control circuits, and automatically operated in synchronism with the periods of opening and closing of the switch means, for connecting the electroresponslve means for alternating forward and reverse operation so that deflection oi the deflectable member in one direction operates the electro-responsive means in one direction, and deflection of the member in the other direction operates the electro-resmonslve means in the reverse direction, in which the switch means includes a contact directionally movable by the deflectaole member, a pair of contacts for engagement with the first contact, and includes means ior periodically alternately bringing the contacts of said pair into the field oi. action of the directionally movable contact, and in which the circuit control means includes a. single pole double throw switch.

aeearoc 12. In a control device, a. reversible motor; a switch in the circuit of the motor for reversing the same; a relay for closing the circuit to the motor; a deflectable member; a drum having contacts in the relay circuit angularly displaced on its surface to engage the deflectable member in the deflected position; means for periodically moving the deflecting member so that it may close the circuit to the relay; and means for rotating the drum and operating the switch in timed relation to thereby control the direction of rotation of the motor in accordance with the position of the deflectable member.

13. In a control apparatus, a reversible A. C. motor having a continuously excited fleld and a pair of oppositely disposed wire wound shading coils; a relay and selector switch connected in the'circuit with the shading coils; a deflectable member; a drum having contacts in the relay circuit angularly spaced on its surface to engage the defiectable member in deflected position; means for periodically moving the deflectin member so'that it may close the circuit to the relay; and means for rotating the drum and operating the switch in timed relation to thereby control the direction of rotation of the motor in accordance with the position of the deflectable member.

14. In a control apparatus, an electro-responsive means operative in reverse directions; control circuits for controlling the direction of operation of said means; an electron discharge system connected with said control circuits for causing operation of the electro-responsive means; a. deflectable member; means including normally open switch contacts cooperative with the deflecting member for controlling the functioning of the electron discharge system in response to deflection of said deflectable member; means for closing the switch contacts periodically during deflection of the deflectable member in either direction; and circuit control means connected in said control circuits and automatically operative in timed relation with said last-named means for causing the electron discharge system to op.- erate the electro-responsive means in one direction or the other, depending upon the direction of deflection of the deflectable member.

15. In a control apparatus, an electro-responsive means operative in reverse directions; control circuits ior controlling the direction of operation of said means; an electron discharge system connected with said control circuits for causing operation of the electro-responsive means; a deflectable member; means including a normally open switch in operative relation with the deflectable member for controlling the function of the electron discharge system in response to deflection o! the deflectable member; means for closing the switch periodically during deflection of the deflectable member in either direction so that periods of closingdurlng deflection in one direction, it continued during the periods of closing tor deflection in the opposite direction, would alternate with said latter periods of closing'; and circuit control means connected in said control circuits and automatically operative in timed relation with said last-mentioned means for causin the electron discharge system to opcrate the electro-responsive means in one direction or the other, depending upon the direction of deflection of the deflectable member.

KANFRED J. JOHNSON. 

